123 lines
2.3 KiB
C++
123 lines
2.3 KiB
C++
#ifndef STACK_H
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#define STACK_H
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#include <cstdint>
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#include <expected>
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#include <format>
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#include <new>
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#define DEFAULT_STACK_SIZE 4
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enum class StackErr {
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ok,
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bad_alloc,
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empty,
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};
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template<typename T>
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requires std::formattable<T, char>
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class Stack {
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private:
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uint64_t len;
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uint64_t cap;
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T *data;
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public:
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Stack();
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~Stack();
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std::expected<T, StackErr> pop();
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std::expected<T, StackErr> peek();
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StackErr push(T val);
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void print();
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};
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template <typename T>
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requires std::formattable<T, char>
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Stack<T>::Stack() {
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Stack<T> new_stack;
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new_stack.data = new T[DEFAULT_STACK_SIZE];
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new_stack.cap = 0;
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new_stack.len = 0;
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return new_stack;
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}
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template <typename T>
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requires std::formattable<T, char>
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Stack<T>::~Stack() {
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delete[] this->data;
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}
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template <typename T>
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requires std::formattable<T, char>
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StackErr Stack<T>::push(T value) {
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// If not enough space allocate more space
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if (this->len >= this->cap) {
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uint64_t new_capacity = this->cap * 2;
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T *tmp;
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try {
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tmp = new T[new_capacity];
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} catch (const std::bad_alloc& e) {
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return StackErr::bad_alloc;
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}
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for (int i = 0; i < this->len; i++) {
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tmp[i] = this->data[i];
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}
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delete[] this->data;
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this->data = tmp;
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}
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this->data[this->len] = value;
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this->len++;
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return StackErr::ok;
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}
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template <typename T>
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requires std::formattable<T, char>
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std::expected<T, StackErr> Stack<T>::pop() {
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if (this->len == 0) {
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return std::unexpected(StackErr::empty);
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}
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T return_val = this->data[this->len - 1];
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if (this->cap / 4 > this->len) {
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uint64_t new_capacity = this->cap / 2;
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T *tmp;
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try {
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tmp = new T[new_capacity];
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} catch (const std::bad_alloc& e) {
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return std::unexpected(StackErr::bad_alloc);
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}
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for (int i = 0; i < this->len; i++) {
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tmp[i] = this->data[i];
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}
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delete[] this->data;
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this->data = tmp;
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}
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return std::expected(return_val);
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}
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template <typename T>
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requires std::formattable<T, char>
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std::expected<T, StackErr> Stack<T>::peek() {
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if (this->len == 0) {
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return std::unexpected(StackErr::empty);
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}
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return std::expected(this->data[this->len - 1]);
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}
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#endif // !ST
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